<template>
    <div class="app-container">

        <el-button :loading="downloadLoading" style="margin-bottom:20px" type="primary" icon="el-icon-document" @click="handleDownload">Export</el-button>

        <el-table ref="multipleTable"
                  v-loading="listLoading"
                  :data="list"
                  element-loading-text="Loading"
                  border
                  fit
                  highlight-current-row>
            <el-table-column align="center" label="Id" width="95">
                <template slot-scope="scope">
                    {{ scope.$index }}
                </template>
            </el-table-column>
            <el-table-column label="Main Information" align="center">
                <el-table-column label="Title">
                    <template slot-scope="scope">
                        {{ scope.row.title }}
                    </template>
                </el-table-column>
                <el-table-column label="Author" width="110" align="center">
                    <template slot-scope="scope">
                        <el-tag>{{ scope.row.author }}</el-tag>
                    </template>
                </el-table-column>
                <el-table-column label="Readings" width="115" align="center">
                    <template slot-scope="scope">
                        {{ scope.row.pageviews }}
                    </template>
                </el-table-column>
            </el-table-column>
            <el-table-column align="center" label="Date" width="220">
                <template slot-scope="scope">
                    <i class="el-icon-time"></i>
                    <span>{{ scope.row.timestamp | parseTime('{y}-{m}-{d} {h}:{i}') }}</span>
                </template>
            </el-table-column>
        </el-table>

    </div>
</template>

<script>
	import * as UtilsObj from "/vue/utils/index.js"; 
    const parseTime = UtilsObj.parseTime;
    import { fetchList } from '/vue/api/article.js';
    import * as excel from '/vue/vendor/Export2Excel.js';
    
    module.exports = {
        name: 'MergeHeader',
        data() {
            return {
                list: null,
                listLoading: true,
                downloadLoading: false
            }
        },
        created() {
               this.fetchData();
        },
        methods: {
            fetchData() {
                this.listLoading = true
                fetchList(this.listQuery).then(response => {
                    this.list = response.data.items
                    this.listLoading = false
                })
            },
            handleDownload() {
                this.downloadLoading = true
                    const multiHeader = [['Id', 'Main Information', '', '', 'Date']]
                    const header = ['', 'Title', 'Author', 'Readings', '']
                    const filterVal = ['id', 'title', 'author', 'pageviews', 'display_time']
                    const list = this.list
                    const data = this.formatJson(filterVal, list)
                    const merges = ['A1:A2', 'B1:D1', 'E1:E2']
                    excel.export_json_to_excel({
                        multiHeader,
                        header,
                        merges,
                        data
                    })
                    this.downloadLoading = false
            },
            formatJson(filterVal, jsonData) {
                return jsonData.map(v => filterVal.map(j => {
                    if (j === 'timestamp') {
                        return parseTime(v[j])
                    } else {
                        return v[j]
                    }
                }))
            }
        }
    }
</script>
